Bylaws for car porch in islamabad

Jkchs (g-15) bylaws require maximum 200 sq ft for car porch in a 356 sq yards plot. I think cda uses similar. I need a car space of 360 sq ft (for three cars). I don't wanna use the rear set-back for shifting one car. Can the experts suggest the work around?

Also by law require car porch can't be used as terrace. The car place provides a convenient space for first floor to use as outdoor. What would be the work around here?